Two newly discovered planets look promising for extraterrestrial life

Jan 13, 2015

Illustration: David A. Aguilar (CfA)

By Michelle Starr

While it’s not strictly impossible that life in the universe exists in an as-yet-unknown form (say, silicon-based), we don’t really know how to look for it. We do, however, know how to look for the conditions that have given birth to the life forms we know — that is, the conditions on our home planet, Earth.

This is the Kepler mission: to locate planets enough like Earth to be considered habitable. There are several key factors to this. First, the planets must be in the “Goldilocks” zone — that is, not too hot, not too cold, but juuuust right. This refers to the planet’s orbit position around its star: a distance where it’s not so close that it’s too hot for liquid water, but not so far that it’s so cold all water freezes.

In addition, the planet needs to be rocky — like Earth.

Among the recent crop of eight new Kepler planets discovered in the Goldilocks zone around their stars — announced at a meeting of the American Astronomical Society on January 6 — two are the most similar to Earth of any of the 1,004 Kepler planets identified to date.


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16 comments on “Two newly discovered planets look promising for extraterrestrial life

  • @OP link – The two planets are very far away — 470 light-years from Earth for Kepler-438b and 1,100 light-years for Kepler-442b — which makes analysis challenging.

    At these distances the study is academic. There is negligible prospect of sending probes or humans to them.

    They do however give examples of the sorts of planets we are looking for nearer to the Solar System, and this also shows we are getting better at detecting smaller planets around the size of Earth.

    Kepler-438b is 12 percent bigger than Earth, and completes an orbit of its star every 35 days.

    This has probably been detected because it it is in a short orbit near to its star. – An easier type of planet to detect than one orbiting further out.

    Kepler-442b is about 33 percent larger than Earth, and completes an orbit every 112 days. It receives about two-thirds as much light as Earth, and has a 60 percent chance of being rocky. The team said it has a 97 percent chance of being in the habitable zone.

    This is a longer year, but it looks to be on the cool side. It should have some areas with Earth-like temperatures if it has an atmosphere, if its spin gives it suitable day-lengths, and if it is not tidally locked to its star.



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  • Using Kepler’s third law on Kepler 438B..,

    a^3 = T^2

    ( a = planet’s semimajor axis, or average distance from sun—-T = orbital time in earth years )

    You get..,

    = 0.21 astronomical units from it’s sun.
    =======================================Sounds Mercury like!



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  • Neodarwinian Jan 13, 2015 at 5:23 pm

    You get..,

    = 0.21 astronomical units from it’s sun.
    =======================================Sounds Mercury like!

    The star is a Red Dwarf, which keeps the heat down in this close an orbit, but close orbits are bad news for the inability to retain moons and the potential for tidal locking.

    A tidally locked planet with a 112 Earth-day year, would potentially have days and nights 56 Earth-days long – (depending on the axis). This length of continuous / absence of, sunlight would make for extreme temperatures.



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  • 6
    NearlyNakedApe says:

    I don’t think we’ll have enough time to develop sufficiently advanced technology to migrate the entire human species before we make our planet inhabitable. Furthermore, the biggest problem is us humans. If we migrate to another planet, we’ll bring our “baggage” and the cycle of violence and injustice will just have been moved to a different world.

    I guess that by then the new aphorism will be : Same shit, different planet.



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  • In addition to being a rocky planet with a stable orbit within the habitable zone, presumably it would also have to have a magnetosphere that protects it from the solar wind and allows it to retain an atmosphere and be of a size and in a position where gravitational forces do not effect it such that life cannot exist.

    Planets that possess all of these features are probably so rare that it makes finding another Earth (and not just an Earth-like planet) vanishingly small. As a result our instruments will have to become much more sensitive if we are to be able to narrow the search down to planets that don’t just have a slight possibility of life but a statistically significant probability to make it worth our while trying to communicate with them or send probes, etc.



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  • Ipse Dixit Jan 14, 2015 at 12:41 pm

    As a result our instruments will have to become much more sensitive if we are to be able to narrow the search down to planets that don’t just have a slight possibility of life but a statistically significant probability to make it worth our while trying to communicate with them or send probes, etc.

    The planets described in the OP are far too distant, but there are people working on the idea of sending probes to some of our local star-systems when promising targets have been identified.

    http://www.centauri-dreams.org/?p=14513
    Icarus is the attempt to re-examine the Project Daedalus starship study of the 1970s in light of technological developments in the intervening years. A joint project between the British Interplanetary Society and the Tau Zero Foundation,



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  • There is also the potential that the upcoming James Web Space Telescope (JWST) will be able to detect bio-markers (oxygen/methane) using spectrophotometry. The near future for detecting life on exo-planets will not be from sending probes but rather using larger and more advanced telescopes.



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  • If people here try to calculate properties of these planets from relations, they should bear in mind proportionality constants may vary. Orbital semi-major axes depend on the star’s mass. Planetary temperature at equilibrium with incident starlight depends on planetary albedo. But if the Earth’s sunlight, for example, fell by a third, the absolute temperature would fall by about 10% (30K) by the Stefan-Boltzmann law. That would mean most but by no means all of Earth would regularly be below 0C. But as I say, another planet’s albedo matters.



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  • 12
    Light Wave says:

    Apparently Glasgow University scientists are on the verge of creating synthetic life using some kind of robotic process….don’t know if its been confirmed though and I’m not too great with chemistry but this would have to rock religion’s boat somewhat….if successful….



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  • NearlyNakedApe Jan 14, 2015 at 12:27 pm

    I don’t think we’ll have enough time to develop sufficiently advanced technology to migrate the entire human species before we make our planet inhabitable.

    For reasons of logistics, there is no prospect of migrating the entire human species off Earth, unless we are simply saving the last remnants of it on prior constructed space craft, travelling to commercial, or scientific, planetary, lunar, or cometary outposts.
    At some point in the future, we may be able to send a few chosen individuals to some suitable, nearby, exoplanet, where sustainable bases can be built, but the bulk of the endemic human population will remain on Earth – living or dead!



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  • Furthermore, the biggest problem is us humans. If we migrate to
    another planet, we’ll bring our “baggage” and the cycle of violence
    and injustice will just have been moved to a different world.

    I guess that by then the new aphorism will be : Same shit, different
    planet.

    Yeh! We are the worse thing that ever happened to this universe LOL. Those old Black Holes and Supernovas make us sound like the fart of a tic……..:-)



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  • Jos Gibbons Jan 14, 2015 at 3:12 pm

    Planetary temperature at equilibrium with incident starlight depends on planetary albedo.

    The ability to retain an atmosphere and oceans over the long term, would also have a massive effect on the distribution of temperatures, – as would the rate of the planet’s spin to circulate them.



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